JP4440351B2 - Color video camera, TV door phone and monitoring device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a color video camera having sensitivity up to the near-infrared region, a television doorphone and a monitoring device using the color video camera.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a television door phone that can also know video information of visitors is known. This TV door phone has a monochrome video camera attached to the outdoor unit, and sends a video signal obtained by imaging a visitor etc. with this monochrome video camera to a TV monitor attached to the main unit installed indoors. The video of the visitor is displayed on the screen of the television monitor.
[0003]
In such a conventional monochrome TV door phone, a light emitting diode (LED) has been adopted as illumination for a subject when natural light is low in nighttime or evening. This utilizes the fact that a CCD, which is an image pickup element of the monochrome video camera, has sensitivity in the near infrared region, so that an object illuminated with near infrared light can be imaged. Since a subject such as a visitor illuminated with near-infrared light is not noticed to be illuminated, it is possible to capture an image without giving the visitor discomfort. Moreover, this LED has an advantage that it is cheaper and has a longer life than a light bulb or the like.
[0004]
By the way, to get the color information of the visitors and check the visitors in more detail, color the TV camera attached to the indoor unit and color the TV monitor attached to the outdoor unit. The TV door phone can be colored. For this purpose, a color video camera may be used for the outdoor unit and a color television monitor may be used for the indoor unit.
[0005]
This color video camera has a configuration in which a video signal is obtained from an optical image by a color CCD. As shown in FIG. 13, the spectral sensitivity of this CCD is in the near-infrared light region with a wavelength of 700 nm or more. Therefore, even in a color TV door phone, by using an LED that emits near-infrared light at the time of low illuminance as described above, The same merit as a monochrome TV door phone can be obtained.
[0006]
However, if a subject illuminated by near-infrared light is imaged by a color video camera and the image is projected on a color television monitor, an unnatural color of, for example, blue is obtained. In addition, when the subject is illuminated with ambient light such as natural light in addition to the near-infrared light, the image projected on the color television monitor is in a monotone image of blue and other monotone colors. It is a very unnatural and difficult to see video.
[0007]
In both the monochrome TV doorphone and the color TV doorphone, the illuminance of the infrared light from the LED is always constant, so if the illuminance of the subject changes depending on the surrounding conditions, the shutter control of the video camera By adjusting the function, an image with proper exposure was obtained. However, such adjustment by the shutter control function cannot be followed, and in some cases, an image with an appropriate exposure cannot be obtained.
[0008]
[Problems to be solved by the invention]
In order to color TV doorphones as described above, a color video camera is used to illuminate a subject with near infrared light emitted from a light emitting diode when natural light such as nighttime is low illuminance. When imaged by a color video camera, for example, it becomes an unnatural color of blue. In addition, when the subject is illuminated with ambient light such as natural light in addition to the near-infrared light, the image projected on the color television monitor is in the form of a monochromatic blue image with other monotone colors. There is a problem that the image becomes extremely unnatural and difficult to see. Also, since the illuminance of the infrared light from the LED described above is always constant, if the illuminance of the subject changes depending on the surrounding conditions, it cannot be followed only by adjustment by the shutter control function of the video camera. However, there was a problem that images with appropriate exposure could not be obtained.
[0009]
Therefore, the present invention has been made to solve the above-described problems, and even when a light emitting diode that emits near infrared rays is used as a light source for illuminating a subject when natural light is low, an easy-to-view image is obtained. A color video camera that can obtain images with appropriate exposure at all times, and by using this color video camera, it is easy to monitor subjects such as visitors even when the surroundings are dark, such as at night. It is an object of the present invention to provide a television door phone and a monitoring device that can do the above.
[0010]
[Means for Solving the Problems]
The invention according to claim 1 is a lens for condensing light; a CCD for photoelectrically converting the light collected by the lens to obtain a color image signal; and the color image signal obtained by driving the CCD. A video signal processing unit for applying various processes to create a video signal having a luminance signal and a color signal; A light source that emits infrared light for illumination; infrared light is insensitive and visible light sensitive; A sensor that detects the illuminance of visible light; a determination unit that determines that the illuminance detected by the sensor is less than or equal to a set value; and when the determination unit determines that the illuminance is less than or equal to a set value, Output monochrome video signal Signal processing means;
[0011]
With such a configuration, when the subject is illuminated with near-infrared light when it is dark, such as in the evening or at night, the determination unit has an illuminance of visible light (natural light) detected by the sensor below a set value. It is determined that As a result, the video signal is output instead of the monochrome signal. When this is projected on a color television monitor, it becomes a monochrome image, and all troubles related to color caused by near-infrared light irradiation are eliminated.
[0012]
According to a second aspect of the present invention, there is provided a lens for condensing light; a CCD for photoelectrically converting the light collected by the lens to obtain a color image signal; and the color image signal obtained by driving the CCD. A video signal processing unit for applying various processes to create a video signal having a luminance signal and a color signal; Infrared is not sensitive and visible light is sensitive, A sensor that detects the illuminance of visible light; a first determination unit that determines that the illuminance detected by the sensor has become equal to or less than a first set value; and the illuminance is first determined by the first determination unit. If it is determined that the value is less than the set value, Output monochrome video signal A signal processing unit; a light source that emits infrared rays for illumination; a second determination unit that determines that the illuminance detected by the sensor is equal to or lower than a second set value; and a second determination unit A light source control unit that turns on the light source and emits infrared light when it is determined that the illuminance is equal to or lower than a second set value.
[0013]
With such a configuration, when the second determination unit determines that the illuminance detected by the sensor is equal to or lower than the second set value, the light source control unit turns on the light source (for example, a light emitting diode) to emit infrared light. Irradiate. Here, if the first setting value ≦ the second setting value, the first determination unit determines that the illuminance has become equal to or less than the first setting value when the light source is turned on. Therefore, the video signal is output instead of the monochrome signal, When this is projected on a color television monitor, it becomes a monochrome image, and all troubles related to color caused by near-infrared light irradiation are eliminated.
[0014]
According to a third aspect of the present invention, the first determination unit includes first variable setting means for changing and setting the first set value, and the second determination unit changes the second set value. The second variable setting means for setting is provided.
[0015]
With such a configuration, for example, the user sets the first set value to an arbitrary value by the first variable setting means, and converts the video signal output from the video signal processing unit from a color video signal to a monochrome video. The illuminance of natural light to be converted into a signal is arbitrarily set. Further, the user sets the second set value to an arbitrary value by the second variable setting means, and arbitrarily sets the illuminance of natural light for turning on the light source by the light source control unit.
[0016]
According to a fourth aspect of the present invention, the first set value of the first determination unit is different from the second set value of the second determination unit.
[0017]
With such a configuration, for example, after the light source is turned on and irradiated with infrared rays, the video signal created by the video signal processing unit is replaced with a monochrome video signal.
[0018]
According to a fifth aspect of the present invention, the first setting value of the first determination unit and the second setting value of the second determination unit are the same, and the first determination unit and the second determination value are the same. The determination unit is shared.
[0019]
With such a configuration, the video signal generated by the video signal processing unit is replaced with a monochrome video signal at the same time as the light source is turned on to emit infrared rays.
[0020]
The light source control unit according to a sixth aspect of the invention includes a dimming circuit that controls a current supplied to the light source in accordance with illuminance detected by the sensor.
[0021]
With such a configuration, after the light source is turned on and irradiated with infrared rays, the light control circuit of the light source control unit generates a current to be supplied to the light source according to the illuminance of visible light (natural light) detected by the sensor. In order to control, the illuminance of infrared rays emitted from this light source changes according to the illuminance of visible light. Accordingly, as the area gets darker, the illuminance of infrared rays emitted from the light source increases accordingly, so that the subject imaged by the lens and the CCD does not become insufficiently illuminated, and the shutter control function of the CCD Illuminated at a brightness within a range that can be followed.
[0024]
Claim 7 The invention includes: a color video camera according to any one of claims 1 to 6; a slave unit having an infrared light source that illuminates a subject imaged by the color video camera; and output from the color video camera. A master unit having a color television monitor that processes a video signal and projects an image of a subject captured by the color video camera on a screen.
[0025]
With such a configuration, at night, the color video camera captures an object illuminated with infrared rays from the light emitting diode serving as the light source, and the image is monitored as a monochrome image on the color television monitor. Under daylight, the subject is imaged by the color video camera, and this image is monitored as a color image by the color television monitor.
[0026]
Claim 8 The invention provides a color video camera according to any one of claims 1 to 6; a light source that emits infrared light that illuminates a subject imaged by the color video camera; and a video signal output from the color video camera; And a color television monitor for projecting an image of a subject imaged by the color video camera on a screen.
[0027]
With such a configuration, at night, the color video camera captures an object illuminated with infrared rays from the light emitting diode serving as the light source, and the image is monitored as a monochrome image on the color television monitor. Under daylight, the subject is imaged by the color video camera, and this image is monitored as a color image by the color television monitor.
[0028]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a color video camera according to a first embodiment of the present invention. Reference numeral 1 denotes an image pickup unit that picks up an image of a visitor 100 that is a subject and obtains a video signal 50. The lens 11 collects the reflected light of the visitor 100, and photoelectrically converts the light collected and incident by the lens 11 And a CCD 12 for making a color video signal 50. 2 drives the CCD 12, performs various processes on the video signal 50 obtained from the CCD 12, creates and outputs a video signal 60 composed of a luminance signal and a color signal, and creates it by the determination signal 70 of the determination unit 4. A video signal processing unit having a function of removing a color signal component from a video signal, 3 is a CdS sensor (sensor) for detecting visible light, and 4 is an illuminance level of visible light detected by the CdS sensor 3 being lower than a set value. A determination unit 5 for determining whether or not a light emitting diode (LED) that emits near infrared rays for illuminating the visitor 100, and 100 is a visitor as a subject. However, the video signal processing unit 2 incorporates signal processing means. The light emitting diode (LED) constitutes a light source.
[0029]
FIG. 2 shows an example of the spectral characteristics of the CdS sensor 3. It can be seen that there is sensitivity in the visible light region with a wavelength in the range of 400 nm to 700 nm, but there is no sensitivity to infrared rays with a wavelength of 700 nm or more.
[0030]
FIG. 3 is a characteristic diagram showing the relationship between the resistance value of the CdS sensor 3 and the illuminance. The CdS sensor 3 has a characteristic that its resistance value decreases as the illuminance increases. The numbers in the figure are parameters and indicate the type of the CdS sensor 3.
[0031]
Next, the operation of the present embodiment will be described. When the illuminance of natural light is sufficiently high, such as when the visitor 100 that is the subject is illuminated by natural light in the daytime, the lens 11 of the imaging unit 1 collects the reflected light of the visitor 100 and places it on the CCD 12. In order to form an optical image, the CCD 12 outputs a color video signal 50 of the visitor 100 to the video signal processing unit 2. The video signal processing unit 2 performs various processes on the input video signal 50 to create a video signal 60 composed of a luminance signal and a color signal, and outputs the video signal 60.
[0032]
Here, when the illuminance of natural light around the visitor 100 is sufficiently high, the resistance value of the CdS sensor 3 is also low. When the determination unit 4 detects the current illuminance of visible light from the change in the resistance value of the CdS sensor 3 and determines that the detected illuminance is less than or equal to a preset reference illuminance, the determination signal 70 is displayed as the video signal processing unit 2. Output to. However, since the CdS sensor 3 has sensitivity to visible light as shown in FIG. 2 and does not have sensitivity to infrared light, the illuminance sensed by the CdS sensor 3 is visible light. Accordingly, when the illuminance of visible light is sufficiently high, the color video signal 60 is output from the video signal processing unit 2.
[0033]
FIG. 4 is a circuit diagram illustrating a detailed example of the determination unit 4 described above. Since a voltage is applied to the CdS sensor 3 via the resistor R1, when the illuminance of natural light input to the CdS sensor 3 changes, the resistance value of the CdS sensor 3 changes and the terminal voltage changes. The comparator 41 compares this terminal voltage with a reference voltage Vf that gives a reference illuminance. That is, when the illuminance decreases and the resistance value of the CdS sensor 3 increases as shown in FIG. 3, the terminal voltage increases. When the terminal voltage exceeds the reference voltage Vf, the comparator 41 Sets its output high. For this reason, the transistor 42 is turned on, and a low-level determination signal 70 is output from its collector. The video signal processing unit 2 causes the color signal to flow to the ground side by the determination signal 70 at the low level, and removes the color signal from the video signal 60 to obtain a monochrome video signal having only a luminance signal. The reference voltage Vf that gives the reference illuminance can be set to an arbitrary value by adjusting the volume VR (first variable setting means).
[0034]
Further, when the illuminance of the natural light increases and the resistance value of the CdS sensor 3 decreases as shown in FIG. 3, the terminal voltage decreases, and when the terminal voltage falls below the lighting reference voltage Vf, The terminal voltage of the comparator 41 becomes low level, the transistor 42 is turned off, and the low level determination signal 70 output from the collector thereof is inverted to high level. As a result, the color signal of the video signal processing unit 2 is restored, and the video signal 60 returns to the color video signal including the luminance signal and the color signal.
[0035]
By the way, when the illuminance of natural light around the visitor 100 becomes low, such as in the evening or at night, even if the shutter function speed of the CCD 12 is slowest, there is no amount of light incident on the CCD 12. Since the recorded image becomes dark, the LED 5 is turned on, and the visitor 100 is illuminated by the near infrared rays emitted from the LED 5. Since the CCD 12 of this example has sensitivity to near infrared rays, when the near infrared rays are emitted from the LED 5, the amount of light incident on the CCD 12 increases accordingly, so that an image with appropriate exposure can be obtained. It should be noted that even when there is no natural light at night, such as at night, the LED 5 can emit a sufficient amount of light to image the visitor 100 with only near infrared rays emitted from the LED 5.
[0036]
FIG. 5 is a characteristic diagram showing a spectrum example of near-infrared light emitted from the LED 5 described above. It can be seen that the near infrared light emitted from the LED 5 has a center wavelength of 860 nm.
[0037]
In this example, the illuminance of the natural light from which the determination unit 4 outputs the above-described determination signal 70 is equal to or less than the illuminance of the natural light at which the LED 5 is turned on. Accordingly, the video signal 60 output from the video signal processing unit 2 is switched from the color video signal to the monochrome video signal at the same time as the LED 5 is turned on or shortly after the LED 5 is turned on.
[0038]
By the way, when the illuminance of natural light around the visitor 100 changes from a low state to a high state as at dawn, the determination signal 70 output from the determination unit 4 returns to a high level. For this reason, the video signal processing unit 2 outputs the color signal together with the luminance signal, and converts the video signal 60 into a color video signal. At this time, the LED 5 is also turned off, the visitor 100 is illuminated only with natural light, and the color image of the visitor 100 is displayed on the screen of the color television monitor to which the video signal 60 is input.
[0039]
According to the present embodiment, when the LED 5 is turned on and the visitor 100 is illuminated with natural light mixed with near-infrared light or only near-infrared light, the video signal processing unit 2 outputs the light. When the video signal 60 becomes a monochrome video signal, a monochrome image of the visitor 100 is captured on the screen of the color television monitor, so that the trouble of unnatural colors caused by the near-infrared light irradiation is eliminated. Makes it easier to see the person's video.
[0040]
Note that while the ratio of natural light is larger than the ratio of near-infrared light emitted from the LED 5, it is not so easy to see even a color image, so the lighting timing of the LED 5 and the switching timing to a monochrome image are not necessarily matched. Not necessary. For this reason, the above effect is achieved even when the timing at which the video signal 60 output from the video signal processing unit 2 changes to a monochrome video signal becomes a natural light illuminance slightly lower than the natural light illuminance when the LED 5 is lit. Obtainable.
[0041]
FIG. 6 is a block diagram showing the configuration of the second embodiment of the color video camera of the present invention. In this example, an LED control unit 6 that controls the LED 5 according to the illuminance detected by the CdS sensor 3 is provided. The other configuration is the same as that of the first embodiment shown in FIG. 1 and performs the same operation. However, the LED 5 constitutes a light source, and the LED control unit 6 constitutes a light source control unit and incorporates a second determination unit.
[0042]
Next, the operation of the present embodiment will be described. When the illuminance of natural light detected by the CdS sensor 3 falls below a preset lighting illuminance (second set value), the LED control unit 6 turns on the LED 5. The lighting reference illuminance is set in the vicinity of the illuminance in which the exposure of the video signal 50 obtained from the CCD 12 of the imaging unit 1 becomes darker as the illuminance of natural light around the visitor 100 decreases. Accordingly, when the illuminance of natural light around the visitor 100 decreases, such as in the evening, the LED control unit 6 automatically turns on the LED 5 to illuminate the visitor 100, so that an image obtained from the CCD 12 is obtained. The underexposure of the signal 50 is eliminated. Here, the lighting reference illuminance set in the LED control unit 6 is equal to or slightly larger than the reference illuminance (first set value) set in the determination unit (first determination unit) 4. If set, the video signal 60 output from the video signal processing unit 2 is changed to a monochrome video signal after the LED 5 is turned on.
[0043]
Moreover, when the illuminance of natural light around the visitor 100 changes from a low state to a high state as at dawn, the determination signal 70 output from the determination unit 4 returns to a high level, and the illuminance of the natural light increases. It exceeds the lighting standard illuminance described above. Thereby, the LED control unit 6 performs control to turn off the LED 5, and the video signal processing unit 2 outputs the color signal together with the luminance signal and returns the video signal 60 to the color video signal. A color image of the visitor 100 is displayed on the screen of the television monitor.
[0044]
FIG. 7 is a circuit diagram showing a detailed configuration example of the LED control unit 6 described above. Since a voltage is applied to the CdS sensor 3 via the resistor R1, when the illuminance of natural light incident on the CdS sensor 3 changes, the resistance value of the CdS sensor 3 changes as shown in FIG. The voltage changes. The comparator 61 compares the terminal voltage with a reference voltage Vf that gives a lighting reference illuminance. That is, when the illuminance decreases and the resistance value of the CdS sensor 3 increases, the terminal voltage increases. When the terminal voltage exceeds the lighting reference voltage Vf, the comparator 61 increases its output. To level. Therefore, the transistor 62 is turned on, a current flows through the resistor 5 through the resistor R5, and the LED 5 is lit. Further, when the illuminance increases and the resistance value of the CdS sensor 3 decreases, the terminal voltage decreases. When the terminal voltage falls below the lighting reference voltage Vf, the output voltage of the comparator 61 becomes low. At the level, the transistor 42 is turned off and the LED 5 is turned off. The reference voltage Vf that gives the lighting reference illuminance can be adjusted to an arbitrary value by adjusting the volume VR (second variable setting means).
[0045]
According to the present embodiment, the LED 5 is lit by the LED control unit 6 in synchronization with the timing at which the video signal 60 output from the video signal processing unit 2 changes to a monochrome video signal or slightly earlier, The CCD 12 can always output an optimally exposed video signal without imposing a burden on the user, and the video signal processing unit 2 interlocks with the lighting of the LED 5 to make the video signal easy to see for the user. 60 can be switched from color to monochrome video signal.
[0046]
In the second embodiment described above, as shown in FIG. 6, the LED control unit 6 determines whether the illuminance detected by the CdS sensor 3 is lower than the lighting reference illuminance, and the determination unit 4 determines whether the illuminance is detected by the CdS sensor. 3, it is determined whether the detected illuminance is lower than the reference illuminance, but when the lighting reference illuminance and the reference illuminance are matched, the determination operation in the LCD controller 6 is omitted, and FIG. As shown in the figure, the same effect can be obtained even if the LCD control unit 6 performs on / off control of the LED 5 using the determination result of the determination unit 4.
[0047]
FIG. 9 is a circuit diagram showing the main part of the configuration of the fourth embodiment of the color video camera of the present invention. The LED control unit 6 of this example performs on / off control of the LED 5 and also performs dimming control of the LED 5. Other configurations are the same as those of the second embodiment shown in FIG.
[0048]
Next, the operation of the present embodiment will be described. Since a voltage is applied to the CdS sensor 3 via the resistor R1, when the illuminance of natural light changes, the resistance value of the CdS sensor 3 changes as shown in FIG. 3, and its terminal voltage changes. The comparator 61 compares the terminal voltage with the lighting reference voltage Vf that gives the lighting reference illuminance. That is, when the illuminance decreases and the resistance value of the CdS sensor 3 increases, the terminal voltage increases. When the terminal voltage exceeds the lighting reference voltage Vf, the comparator 61 increases its output. To level. For this reason, the transistor 62 is turned on, and current flows through the resistor R5, the LED5, the transistor 62, and the transistor 64, so that the LED5 is lit.
[0049]
Here, as shown in FIG. 3, the resistance value of the CdS sensor 3 increases as the illuminance of natural light decreases, so the terminal voltage of the CdS sensor 3 increases as the illuminance of natural light decreases. Since the terminal voltage of the CdS sensor 3 is applied to the base of the transistor 64 through the amplifier 63, the lower the illuminance, the higher the voltage applied to the base of the transistor 64 and the lower the conduction resistance of the transistor 64. For this reason, the lower the illuminance, the larger the current flowing through the transistor 64, the larger the current flowing through the LED 5, and the illuminance of near infrared light emitted from the LED 5 increases.
[0050]
According to the present embodiment, the LED control unit 6 turns on and off the LED 5 according to the illuminance of natural light around a visitor (not shown), and near-infrared light emitted from the LED 5 when the ambient illuminance is low. Therefore, the visitor can always be illuminated with the optimum illuminance. Thereby, the illumination which the shutter control of CCD12 can follow is given to the visitor 100, and the image | video of appropriate exposure can always be obtained. Other operations are the same as those of the second embodiment shown in FIG.
[0051]
FIG. 10 is a block diagram showing the configuration of the fifth embodiment of the color video camera of the present invention. The CCD 12 of the imaging unit 1 is for color, and an optical image condensed by the lens 11 is converted into a color video signal 50 and output to the video signal processing unit 2. The video signal processing unit 2 applies various processes to the color video signal 50 to create a color video signal 60 and outputs it. When the surroundings of the visitor 100 become dark, the dimming circuit 7 detects this by the CdS sensor 3 and turns on the incandescent bulb. The dimming circuit 7 controls the current that flows through the incandescent lamp 30 according to the illuminance of natural light around the visitor 100 detected by the CdS sensor 3. That is, when the illuminance of natural light around the visitor 100 decreases, the current flowing through the incandescent bulb 30 is increased, and the light emitted from the incandescent bulb 30 is increased. Further, when the illuminance of natural light around the visitor 100 increases, the current flowing through the incandescent bulb 30 is reduced, and the light emitted from the incandescent bulb 30 is weakened. In this way, the brightness is adjusted so that the illumination of the visitor 100 by the incandescent bulb 30 is always appropriate.
[0052]
According to the present embodiment, how the shutter control of the CCD 12 of the imaging unit 1 is performed by giving the visitor 100 illumination with appropriate intensity according to the illuminance around the visitor 100. Therefore, it is possible to always obtain an image with appropriate exposure. In the case of this example, the same effect can be obtained when a CCD is used for monochrome and a monochrome video camera is used.
[0053]
Note that the same effect can be obtained when the CCD 12 is used for monochrome and the video camera is used for monochrome. In this case, the illumination light source is other than the one that emits visible light such as an incandescent light bulb. In addition, even when an LED that emits near-infrared light is used, the above effect can be obtained without an unnatural color image.
[0054]
FIG. 11 is a block diagram showing a configuration of an embodiment of the television door phone of the present invention. The TV door phone is composed of a base unit 9 installed on the indoor side and a slave unit 8 installed on the outdoor side, and both are connected by a cable 10. The cordless handset 8 includes the same color video camera 81, doorbell button switch 82, microphone 83 that picks up the voice of a visitor (not shown), and the respondent as described in any of FIGS. 1, 6, 8, and 9. Of the speaker 84 and the LED for illuminating the visitor (this LED has the same characteristics as the LED 5 described in FIGS. 1, 6 and 9). The color video camera 81 is connected to a CdS sensor 3 that detects the illuminance of visible light. The base unit 9 includes a color TV monitor 91 that displays a visitor's video, a speaker that outputs a visitor's voice and a handset 92 that is integrally attached with a microphone that collects the visitor's voice, and a speaker that outputs a ringing tone. 95.
[0055]
During a period of low natural light such as nighttime, the LED 85 is lit to illuminate a visitor (not shown). The color video camera 81 images a visitor (not shown) that is illuminated with near infrared light emitted from the LED 85. At this time, when the illuminance of natural light detected by the CdS sensor 3 becomes low enough to turn on the LED 85, the color video camera 81 switches the color video signal output so far to a monochrome video signal, Send to parent unit 9. The base unit 9 inputs the input video signal to the color television monitor 91 and displays a monochrome image of the visitor on the screen.
[0056]
The call with the visitor can be performed without any trouble by the speaker 84 and the microphone 83 of the slave unit 8 and the handset 92 of the master unit 9. When the visitor presses the button switch 82, a ringing tone is generated from the speaker 95 of the master unit.
[0057]
According to the present embodiment, when natural light such as nighttime is low illuminance, a visitor is illuminated and imaged with near-infrared light from the LED 85. At this time, a video signal output from the color video camera 81 is used. Since the video is switched to a monochrome video signal, the video of the visitor displayed on the color TV monitor 91 is monochrome, so the screen is very easy to see and the user can easily check the appearance of the visitor. . In addition, when the illuminance of natural light is low, such as at night, the visitor is illuminated and imaged by near-infrared light from the LED 85, so that the visitor can be checked without being noticed and feeling uncomfortable. . Furthermore, since an inexpensive and long-life light source such as the LED 85 can be used, maintenance of the apparatus can be facilitated and running costs can be kept low. When the color video camera shown in FIG. 6 or FIG. 9 is used, on / off of the LED 85 and dimming are automatically controlled according to the illuminance, so that the usability is improved.
[0058]
FIG. 12 is a block diagram showing the configuration of an embodiment of the monitoring apparatus of the present invention. 21 is the same color video camera as described in any of FIGS. 1, 6, 8, and 9, which always captures and monitors a predetermined range, and 22 is a color video imaged by the color video camera 21. A color television monitor, 23 is a video tape recorder (VTR) that records color images captured by the color video camera 21, and 24 is an LED that emits near-infrared light, which is a light source for illuminating the monitoring range (this LED 85 is shown in FIG. The characteristics are similar to those of the LED 5 described with reference to FIGS. The color video camera 21 is connected to a CdS sensor 3 that detects the illuminance of visible light.
[0059]
Next, the operation of the present embodiment will be described. Since the color video camera 11 has the same structure as that shown in any of FIGS. 1, 6, 8, and 9, near infrared rays are emitted from the LED 24 without being noticed by the other party at night. The monitoring range is imaged by the color video camera 21 by illuminating with, and the obtained monochrome video signal is sent to the color television monitor 22 to display the monochrome video in the monitoring range on the screen.
[0060]
The LED 24 is turned off during a period with sufficient illuminance such as daytime. The color video camera 21 captures an unillustrated visitor illuminated with natural light, and displays the obtained video signal on the screen of the color television monitor 22. It is also possible to record an image captured by the color video camera 21 using the VTR 23 and reproduce it later.
[0061]
In the present embodiment, when the natural light is low illuminance such as at night, the monitoring range is illuminated with near infrared light from the LED 24 to capture an image. At this time, the video signal output from the color video camera 21 is monochrome. Since the video signal is switched, the video of the intruder displayed on the color television monitor 22 is monochrome, so that the screen is very easy to see, and the supervisor can easily check the appearance of the intruder. In addition, when the illuminance of natural light is low, such as at night, the intruder is illuminated and imaged by the near-infrared light of the LED 24, so the intruder can be checked without being noticed and feeling uncomfortable. Furthermore, since an inexpensive and long-life light source such as the LED 24 can be used, the maintenance of the apparatus can be facilitated and the running cost can be kept low. When the color video camera shown in FIG. 6 or FIG. 9 is used, on / off and dimming of the LED 24 are automatically controlled according to the illuminance, so that the usability is improved.
[0062]
【The invention's effect】
As described above, according to the first aspect of the present invention, when a light emitting diode that emits near-infrared light is used as a light source for illuminating a subject when natural light is low, a video signal output from the video signal processing unit is monochrome. Since switching to the video signal, it is possible to obtain an easy-to-view video that is free from color problems caused by irradiation with near infrared light.
[0063]
According to the second, fourth, and fifth aspects of the invention, when the natural light is low, the subject is automatically illuminated with near infrared light emitted from the light emitting diode, and the video signal output from the video signal processing unit is displayed. Since switching to the monochrome video signal, it is possible to easily obtain an easy-to-view video without any color trouble caused by irradiation with near-infrared light without placing a burden on the user.
[0064]
According to the invention of claim 3, the illuminance of the natural light that gives the illumination of the light source to the subject can be optimally adjusted according to the use situation, and the video signal obtained by imaging is changed from the color video signal to the monochrome video signal. The illuminance of natural light to be adjusted can be optimally adjusted according to the use situation, and usability can be improved.
[0065]
According to the invention of claim 6, when the natural light is low, the subject is automatically illuminated with near infrared light emitted from the light emitting diode, and the video signal output from the video signal processing unit is converted into a monochrome video signal. Therefore, it is possible to easily obtain an easy-to-view image without any color trouble caused by irradiation with near-infrared light without imposing a burden on the user, and the illuminance of the near-infrared light emitted from the light-emitting element can be increased. Since it is changed according to the illuminance of the natural light, it is possible to always obtain a monochrome video signal with proper exposure.
[0067]
Claims 7 and 8 According to the invention, since the color video camera according to any one of claims 1 to 6 is used, when the natural light is low illuminance at night or the like, the monitoring range is imaged without being noticed by an intruder, Easy-to-view monochrome images can be easily monitored, and light source diodes (LEDs) that emit infrared light can be used as light sources when the natural light is low, such as at night, making maintenance of the device easier And the running cost can be reduced.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of a color video camera according to a first embodiment of the present invention.
FIG. 2 shows an example of spectral characteristics of the CdS sensor shown in FIG.
FIG. 3 is a characteristic diagram showing the relationship between the resistance value and illuminance of the CdS sensor shown in FIG. 1;
4 is a circuit diagram showing a detailed example of a determination unit shown in FIG. 1;
5 is a characteristic diagram showing a spectrum example of near-infrared light emitted from the LED shown in FIG. 1. FIG.
FIG. 6 is a block diagram showing a configuration of a color video camera according to a second embodiment of the present invention.
7 is a circuit diagram showing a detailed configuration example of an LED control unit shown in FIG. 6;
FIG. 8 is a block diagram showing the configuration of a color video camera according to a third embodiment of the present invention.
FIG. 9 is a circuit diagram showing the main part of the configuration of a color video camera according to a fourth embodiment of the present invention.
FIG. 10 is a block diagram showing a configuration of a color video camera according to a fifth embodiment of the present invention.
FIG. 11 is a block diagram showing a configuration of an embodiment of a television doorphone according to the present invention.
FIG. 12 is a block diagram showing the configuration of an embodiment of the monitoring apparatus of the present invention.
FIG. 13 is a characteristic diagram showing an example of spectral sensitivity characteristics of a color CCD.
[Explanation of symbols]
1 Imaging unit
2 Video signal processor
3 CdS sensor
4 judgment part
5, 24, 85 LED
6 LED controller
7 Light control circuit
8 Child machine
9 Master unit
11 Lens
12 CCD
21, 81 Color video camera
22, 91 Color TV monitor
30 Incandescent light bulb

Claims (8)

A lens that collects light;
A CCD that photoelectrically converts light collected by this lens to obtain a color video signal;
A video signal processing unit that applies various processes to the color video signal obtained by driving the CCD to create a video signal having a luminance signal and a color signal;
A light source that emits infrared light for illumination;
A sensor for detecting the illuminance of visible light, which is not sensitive to infrared light and sensitive to visible light;
A determination unit that determines that the illuminance detected by the sensor is equal to or less than a set value;
A signal processing unit that outputs a monochrome video signal when the determination unit determines that the illuminance is equal to or less than a set value;
A color video camera comprising: A lens that collects light;
A CCD that photoelectrically converts light collected by this lens to obtain a color video signal;
A video signal processing unit that applies various processes to the color video signal obtained by driving the CCD to create a video signal having a luminance signal and a color signal;
A sensor for detecting the illuminance of visible light, which is not sensitive to infrared light and sensitive to visible light;
A first determination unit that determines that the illuminance detected by the sensor is equal to or less than a first set value;
Signal processing means for outputting a monochrome video signal when the first determination unit determines that the illuminance is equal to or lower than a first set value;
A light source that emits infrared light for illumination;
A second determination unit that determines that the illuminance detected by the sensor has become equal to or less than a second set value;
A light source control unit that turns on the light source and emits infrared light when the second determination unit determines that the illuminance is equal to or lower than a second set value;
A color video camera comprising:   The first determination unit includes first variable setting means for changing and setting the first setting value, and the second determination unit is configured to change and set the second setting value. 3. A color video camera according to claim 2, further comprising variable setting means.   3. The color video camera according to claim 2, wherein the first setting value of the first determination unit is different from the second setting value of the second determination unit.   The first setting value of the first determination unit and the second setting value of the second determination unit are made the same, and the first determination unit and the second determination unit are made common. The color video camera according to claim 4.   The color video camera according to claim 2, wherein the light source control unit includes a dimming circuit that controls a current supplied to the light source in accordance with illuminance detected by the sensor. A slave unit comprising: a color video camera according to any one of claims 1 to 6; and a light source that emits infrared light that illuminates a subject imaged by the color video camera;
  A master unit having a color television monitor that processes a video signal output from the color video camera and displays an image of a subject imaged by the color video camera on a screen;
A TV door phone comprising: A color video camera according to any one of claims 1 to 6;
  A light source that emits infrared light to illuminate a subject to be imaged by the color video camera;
  A color television monitor that processes a video signal output from the color video camera and displays an image of a subject captured by the color video camera on a screen;
  A monitoring apparatus comprising:

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